Here's how the foresight theory could explain the most common visual illusions — geometric illusions that involve shapes: Something called the Hering illusion, for instance, looks like bike spokes around a central point, with vertical lines on either side of this central, so-called vanishing point.

Since we aren't actually moving and the figure is static, we misperceive the straight lines as curved ones.

"Evolution has seen to it that geometric drawings like this elicit in us premonitions of the near future," Changizi said. "The converging lines toward a vanishing point (the spokes) are cues that trick our brains into thinking we are moving forward — as we would in the real world, where the door frame (a pair of vertical lines) seems to bow out as we move through it — and we try to perceive what that world will look like in the next instant."

Grand unified theory

In real life, when you are moving forward, it's not just the shape of objects that changes, he explained.

Other variables, such as the angular size (how much of your visual field the object takes up), speed and contrast between the object and background, will also change.

For instance, if two objects are about the same distance in front of you, and you move toward one of the objects, that object will speed up more in the next moment, appear larger, have lower contrast (because something that is moving faster gets more blurred), and literally get nearer to you compared with the other object.

Changizi realized the same future-seeing process could explain several other types of illusions.

In what he refers to as a "grand unified theory," Changizi organized 50 kinds of illusions into a matrix of 28 categories.

The results can successfully predict how certain variables, such as proximity to the central point or size, will be perceived.

Changizi says that finding a theory that works for so many different classes of illusions is "a theorist's dream."

Most other ideas put forth to explain illusions have explained one or just a few types, he said.

The theory is "a big new player in the debate about the origins of illusions," Changizi told LiveScience. "All I'm hoping for is that it becomes a giant gorilla on the block that can take some punches."